The present invention relates to compositions which may be applied to articles of manufacture to provide anti-static and softening benefits to fabrics dried in an automatic clothes dryer. More specifically, the present invention relates to a non-cationic conditioning composition which provides effective anti-static control through a drying cycle period and articles made therefrom which exhibit good storage stability.
Cationic anti-static conditioning compounds and compositions designed for application to fabrics in an automatic dryer are well known in the art. The majority of the commercially available tumble dryer articles contain one or a multiple of cationic surfactants. A few non-cationic containing compounds have been incorporated into fabric compositions in an attempt to improve biodegradability and commercial production.
For example, U.S. Pat. No. 4,209,549 discloses a highly ethoxylated nonionic as an anti-static agent which is preferably admixed with mixtures of glycerides and glyceride-fatty alcohol to provide a fabric softening aspect to the composition. The ethoxylated nonionic disclosed in this patent has at least 20 ethoxy groups per molecule. This composition has shown either poor antistatic efficacy during the drying cycle or poor storage properties, or both.
U.S. Pat. No. 5,145,595 discloses an anti-static softening composition for use in automatic clothes dryers comprising an ethoxylated alcohol, a fatty alcohol and a stabilizer which is a particulate solid and prevents any substantial release of the ethoxylated alcohol-fatty alcohol mixture. Again, the ethoxylated alcohol has at least 20 ethoxy groups per molecule. Furthermore, the particulate stabilizer adversely effects the process of coating the composition onto a dryer article.
GB 1,482,782 discloses fabric conditioning compositions that impart softening and crispness to the fabric. The compositions contain an oil-soluble nonionic surfactant having an HLB of less than 11 and a crisping component insoluble in water that may be a fatty alcohol, a fatty acid, or an insoluble (calcium or magnesium) soap of a fatty acid. The composition may be dispensed from a hollow sponge, a bag or a sheet substrate, or manually scattered, in a granular form, onto the fabric before the start of the drying cycle. The insoluble calcium or magnesium soap of a fatty acid can build up as an undesirable residue on treated fabrics. The oil-soluble nonionic surfactant is being used for softening and not for antistatic protection. The use of a nonionic surfactant with an HLB of less than 11 provides ineffective antistatic control.
U.S. Pat. 5,399,271 discloses a fabric conditioning composition for automatic clothes dryers containing a fatty component which comprises a) fatty acid mono-, di-, and tri-glycerides and-or fatty acids and-or fatty alcohols in admixture with b) fatty alcohol alkoxylates and-or fatty acid esters of monohydric alcohols. The compositions of fatty acids or fatty alcohols and alcohol alkoxylates suffer the similar deficiency shown by the compositions taught in U.S. Pat. No. 4,209,549, in that the compositions are ineffective anti-static controls throughout the drying cycle and have poor storage properties.
U.S. Pat. No. 5,376,287 discloses dryer-activated fabric softening compositions and articles for use in an automatic clothes dryer which comprise (a) a highly ethoxylated sugar derivative and (b) a carboxylic acid salt of tertiary amine. The free amine residue produced from processing the carboxylic acid salt of tertiary amine can result in odor problems and provide poorer softening performance.
It has now surprisingly been found that anionic surfactants, which are individually unsuitable as antistatic fabric softeners, can be combined with selected nonionic surfactants (likewise poor and antistatic agents when used alone in the drying cycle), to form mixtures capable of providing an excellent antistatic efficacy throughout the entire drying cycle while also exhibiting good storage stability.